The U.S. Supreme Court threw out a challenge to a judge-drawn voting map that might help Democrats pick up a seat from Virginia in the U.S. House.

The unanimous ruling Monday said the state’s Republican congressional delegation couldn’t press an appeal seeking to reinstate an earlier map drawn by the state legislature. That map helped Republicans capture eight of Virginia’s 11 U.S. congressional districts in the 2012 and 2014 elections.

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In ordering the new map, a lower court said race played too much of a role when the legislature drew the boundaries for the 3rd District, held by Democratic Representative Bobby Scott. Mapmakers consolidated black, mostly Democratic voters into Scott’s district so that it stretched from north of Richmond southeast to Norfolk, about 100 miles (161 kilometers) away. That improved Republican prospects in neighboring districts.

Virginia’s Democratic Attorney General Mark Herring didn’t appeal that ruling, but the state’s Republican representatives took the matter to the Supreme Court.

The Supreme Court ruling said the Republican representatives lacked enough of a stake in the litigation to give them the right to appeal.

Under the new map, the southeastern 4th District, which has been represented by Republican Randy Forbes since 2001, will lean Democratic after absorbing more than 313,000 people from Scott’s district. Forbes is leaving the 4th District and seeking election in the nearby 2nd District this year.

In throwing out the appeal, Justice Stephen Breyer said Forbes’ lawyers had submitted a letter that said the representative would run in the 2nd District even if the original map were reinstated.

"Given this letter, we do not see how any injury that Forbes might have suffered is likely to be redressed by a favorable judicial decision," Breyer wrote.

Breyer also rejected arguments that other districts represented by Republican Representatives Rob Wittman and David Brat would be flooded with Democratic voters, making their re-election less likely. Breyer said neither lawmaker had shown evidence supporting that contention.

The case is part of the fallout from a 2013 Supreme Court ruling that invalidated a key part of the Voting Rights Act. The ruling undercut the requirement that all or parts of 15 states get federal approval before changing their voting rules.

The original district map was created before the 2013 ruling, and its Republican architect said the 3rd District’s racial composition was necessary to ensure compliance with the federal approval requirement. The map increased the black voting-age population in the district to 56 percent from 53 percent.